JP5229433B2 - Cationic polymerizable adhesive and polarizing plate obtained using the same - Google Patents

Description

  The present invention relates to a cationic polymerizable adhesive that can be used in various applications including the production of polarizing plates used for liquid crystal displays, for example.

  As an adhesive, a cationically polymerizable adhesive that is unlikely to cause curing inhibition due to oxygen in the atmosphere and that can proceed with a curing reaction even after the supply of energy such as ultraviolet rays is stopped is drawing attention. For this reason, the development of cationically polymerizable adhesives has made remarkable progress in recent years, and adhesives suitable for various applications have been reported.

  Examples of the cationic polymerizable adhesive include a glycidyl ether group-containing compound obtained by distilling cyclohexanedimethanol diglycidyl ether, and a glycidyl ether group-containing compound obtained by distilling bisphenol F-type diglycidyl ether. A cationically polymerizable adhesive containing a hydrolyzable silyl group and epoxy group-containing compound and a cationic polymerization initiator and having a chlorine content of 500 ppm is disclosed (for example, see Patent Document 1). .

  As a protective film constituting the polarizing plate, a triacetyl cellulose (TAC) film and a cycloolefin polymer (COP) film have been widely used, and the cationic polymerizable adhesive is used for a TAC film. It has a practically usable level of adhesiveness.

  On the other hand, as a protective film constituting the polarizing plate, in recent years, an inexpensive acrylic resin film is attracting attention instead of a TAC film from the viewpoint of cost reduction or the like (see, for example, Patent Documents 2 to 4).

  However, since the cationic polymerizable adhesive has a low adhesive strength with respect to the acrylic resin film, further improvement in the adhesive strength is desired.

  In addition, since the cationic polymerizable adhesive has a relatively high viscosity, when the adhesive is applied to a protective film or a polarizer, unevenness occurs in the adhesive layer, which affects the optical characteristics of the polarizing plate. It also had problems such as causing

JP 2010-32766 A JP 2008-134384 A JP 2008-134385 A JP 2010-209126 A

  The problem to be solved by the present invention is to provide a cationic polymerizable adhesive having an excellent adhesive strength not only for various protective films but also for an acrylic resin film, and a polarizing plate obtained using the same. It is.

  The present inventors diligently studied various combinations of cationically polymerizable compounds while studying to solve the above problems.

  As a result, the problem of the present invention can be solved only when a specific amount of an oxetane compound having two or more oxetanyl groups and an alicyclic epoxy compound having a specific structure is used with respect to the aromatic glycidyl ether. I found it.

That is, the present invention relates to an aromatic glycidyl ether (A), an oxetane compound (B) having two or more oxetanyl groups, an alicyclic epoxy compound (C) represented by the following general formula (7), and initiation of cationic polymerization. A cationic polymerizable adhesive containing an agent (D), wherein the aromatic glycidyl ether (A) is at least one selected from the group consisting of bisphenol A diglycidyl ether and bisphenol F diglycidyl ether, The oxetane compound (B) is represented by the following general formula ( 2 ), and the oxetane compound (B) is used in the range of 120 to 360 parts by mass with respect to 100 parts by mass of the aromatic glycidyl ether (A). The alicyclic epoxy compound (C) is used in an amount of 35 to 280 parts by mass, and further 2- (3,4-epoxycyclohexyl). One or more selected from the group consisting of titritriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. The present invention relates to a cationically polymerizable adhesive characterized by containing a silane coupling agent (E) having an epoxy group and a polarizing plate obtained by bonding a polarizer and a protective film using the same.

（式（７）中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立に、水素原子又はメチル基を表す。）

(In formula (7), R ¹ , R ² and R ³ each independently represents a hydrogen atom or a methyl group.)

  The cationically polymerizable adhesive of the present invention has excellent adhesive strength not only for various protective films but also for acrylic resin films.

  Further, since the cationic polymerizable adhesive of the present invention has low viscosity and good curability, for example, even when the adhesive of the present invention is applied to a protective film or a polarizer, the adhesive is bonded. Unevenness does not occur in the agent layer, and the optical properties of the polarizing plate are not adversely affected.

  First, the aromatic glycidyl ether (A) will be described.

  The aromatic glycidyl ether (A) is an essential component for providing adhesive strength. As the aromatic glycidyl ether (A), one having two or more glycidyl ether groups is preferably used for imparting good adhesiveness, and more preferably 2 to 6 ones. Examples of the aromatic glycidyl ether (A) include bisphenol A glycidyl ether, bisphenol F glycidyl ether, bisphenol S glycidyl ether, and bisphenol AD glycidyl ether. These aromatic glycidyl ethers may be used alone or in combination of two or more. Among these, bisphenol A type glycidyl ether and bisphenol F type glycidyl ether are preferably used from the viewpoint of improving adhesive strength.

  As the bisphenol A glycidyl ether, for example, bisphenol A diglycidyl ether can be used.

  As the bisphenol F-type glycidyl ether, for example, bisphenol F diglycidyl ether can be used.

  As the aromatic glycidyl ether (A), bisphenol A diglycidyl ether and bisphenol F can be further improved from the viewpoint of further improving the curability and appropriately adjusting the hardness of the cured product and improving the adhesive strength. It is preferable to use one or more selected from the group consisting of diglycidyl ethers.

  In the present invention, the aromatic glycidyl ether (A) and other glycidyl ethers may be used in combination as long as the effects of the present invention are not impaired.

  Examples of the other glycidyl ethers include aliphatic glycidyl compounds having three glycidyl ether groups such as trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, polyglycerol triglycidyl ether, and diglycerol triglycidyl ether, and trimethylol. Two glycidyl ether groups such as propane diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, propylene glycol diglycidyl ether, diethylene glycol diglycidyl ether The glycidyl compound etc. which have can be used.

  Moreover, as said other glycidyl ether, the hydrogenated hydrogenated bisphenol A-type glycidyl ether, hydrogenated bisphenol F-type glycidyl ether, etc. of the said aromatic glycidyl ether (A) can also be used.

  Next, the oxetane compound (B) will be described.

  The oxetane compound (B) is an essential component particularly for imparting low viscosity.

  Moreover, it is essential to use the oxetane compound (B) in a range of 120 to 380 parts by mass with respect to 100 parts by mass of the aromatic glycidyl ether (A) in order to solve the problems of the present invention. Especially, from a viewpoint which can improve adhesive strength further, the range of 140-375 mass parts is more preferable with respect to 100 mass parts of the above-mentioned aromatic glycidyl ether (A), and the range of 140-360 mass parts is still more preferable.

  As said oxetane compound (B), what has 2 or more, preferably 2-4 oxetanyl groups which contribute to cationic polymerization can be used.

  Specifically, as the oxetane compound (B), for example, compounds represented by the following general formulas (1) and (2) can be used.

In the general formulas (1) and (2), each R ¹ is independently a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, an allyl group, an aryl group, or an aralkyl group. , A furyl group or a thienyl group, each R ² independently represents a divalent organic residue, and each Z independently represents an oxygen atom or a sulfur atom.

Examples of the linear, branched or cyclic alkyl group having 1 to 6 carbon atoms represented by R ¹ include a methyl group, an ethyl group, an n- or i-propyl group, an n-, i- or t- group. A butyl group, a pentyl group, a hexyl group, a cyclohexyl group, and the like; and an aryl group such as a phenyl, naphthyl, tolyl, and xylyl group; and an aralkyl group such as a benzyl and phenethyl group It is.

In the general formula (1), examples of the divalent organic residue represented by R ² include a linear, branched or cyclic alkylene group, and a poly (oxy) having 4 to 30 carbon atoms. Alkylene) group, phenylene group, xylylene group, and structures represented by the following general formulas (3) and (4).

The linear, branched or cyclic alkylene group constituting R ² has 1 carbon atom such as methylene group, ethylene group, 1,2- or 1,3-propylene group, butylene group, cyclohexylene group and the like. An alkylene group of ˜15 is preferred. The poly (oxyalkylene) group having 4 to 30 carbon atoms is preferably one having 4 to 8 carbon atoms, for example, a poly (oxyethylene) group or a poly (oxypropylene) group. Is preferred.

In the general formula (3), R ³ represents an oxygen atom, a sulfur atom, CH ₂ , NH, SO, SO ₂ , C (CF ₃ ) ₂ or C (CH ₃ ) ₂ .

In the general formula (4), R ⁴ represents an alkylene group having 1 to 6 carbon atoms, an arylene group, and a functional group represented by the following general formula (5).

  In the general formula (5), a represents an integer of 1 to 6, and b represents an integer of 1 to 15.

  As said general formula (5), it is preferable that b is an integer of 1-3.

  Examples of the oxetane compound having 2 to 4 oxetane ring structures include Aron Oxetane OXT-221, Aron Oxetane OXT-121, Aron Oxetane OXT-223 (manufactured by Toagosei Co., Ltd.), Etanacol OXBP, and Etanacol OXTP. Etanacol OXIPA (above, manufactured by Ube Industries) is commercially available.

  The molecular weight of the oxetane compound (B) is preferably in the range of 100 to 800, more preferably in the range of 100 to 500, from the viewpoint of further improving the low viscosity. For example, when the adhesive of the present invention adheres a polarizer and a protective film, the adhesive layer is usually formed as a thin film (several μm thick) in order to sufficiently cure. This is because the adhesive needs to have a low viscosity in order to uniformly apply the adhesive with the above-mentioned film thickness. The molecular weight of the oxetane compound (B) having two or more oxetanyl groups indicates the molecular weight obtained by calculation from the structural formula.

In addition, as the oxetane compound (B) having two or more oxetanyl groups, among those described above, it is preferable to use those represented by the general formula (1), and in particular, R ¹ in the formula is an ethyl group. And using bis [1-ethyl (3-oxetanyl)] methyl ether in which R ² is methylene makes it possible to further reduce the film thickness of the adhesive after curing, thereby improving curability and adhesiveness. Since it can improve further, it is especially preferable.

  In the present invention, an oxetane compound having one oxetanyl group may be used in combination with the oxetane compound (B) having two or more oxetanyl groups as long as the effects of the present invention are not impaired. .

  As the oxetanyl compound having one oxetanyl group, for example, a compound represented by the following general formula (6) can be used.

(R ¹ in the general formula (6) represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group having 1 to 5 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms.
R ² represents a hydrogen atom, an optionally branched alkyl group having 1 to 10 carbon atoms, an aliphatic cyclic structure, or an aromatic structure. )

Examples of the alkyl group having 1 to 8 carbon atoms that can constitute R ¹ in the general formula (6) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and a 2-ethylhexyl group. Is mentioned.

Examples of the alkoxyalkyl group having 1 to 5 carbon atoms that can constitute R ¹ in the general formula (6) include a methoxymethyl group, an ethoxymethyl group, a propoxymethyl group, a methoxyethyl group, and an ethoxyethyl group. And propoxyethyl group.

Examples of the hydroxyalkyl group having 1 to 6 carbon atoms that can constitute R ¹ in the general formula (6) include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.

The optionally branched alkyl group having 1 to 10 carbon atoms that can constitute R ² in the general formula (6) is a linear alkyl group such as a methyl group, an ethyl group, or a propyl group. And a branched alkyl group such as a 2-ethylhexyl group.

As the aliphatic cyclic structure may constitute R ² in the general formula (6), such as cyclohexyl group and the like. The cyclohexyl group or the like may have an alkyl group or the like instead of a hydrogen atom.

The aromatic structure may constitute R ² in the general formula (6), for example, a phenyl group and the like. The phenyl group or the like may have an alkyl group or the like instead of a hydrogen atom.

  Next, the alicyclic epoxy compound (C) component will be described.

  The alicyclic epoxy compound (C) component is an alicyclic epoxy compound represented by the following general formula (7).

（式（７）中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立に、水素原子又はメチル基を表す。）
なお、前記脂環エポキシ化合物とは、脂環構造にエポキシ基を有する脂環エポキシ基を含有する化合物をいう。

(In formula (7), R ¹ , R ² and R ³ each independently represents a hydrogen atom or a methyl group.)
In addition, the said alicyclic epoxy compound means the compound containing the alicyclic epoxy group which has an epoxy group in an alicyclic structure.

  The alicyclic epoxy compound (C) is an essential component particularly for imparting good adhesive strength to an acrylic resin film.

  Moreover, it is essential to use the alicyclic epoxy compound (C) in the range of 15 to 280 parts by mass with respect to 100 parts by mass of the aromatic glycidyl ether (A) in order to solve the problems of the present invention. . Especially, it is more preferable to use in the range of 20-270 mass parts with respect to 100 mass parts of said aromatic glycidyl ether (A) from a viewpoint which can improve adhesive strength further, and 35-250 mass parts is still more preferable.

  Among the alicyclic epoxy compounds (C), it is preferable to use 1,2: 8,9-diepoxy limonene, particularly from the viewpoint of further improving the adhesive strength to the acrylic resin film. Examples of commercially available products that can be suitably used as the alicyclic epoxy compound (C) include Celoxide 3000 (manufactured by Daicel Chemical Industries, Ltd.).

  In the present invention, other alicyclic epoxy compounds may be used in combination with the alicyclic epoxy compound (C) as long as the effects of the present invention are not impaired.

  As said other alicyclic epoxy compound, the epoxy compound which has 2-4 alicyclic epoxy groups is mentioned, for example.

  As an alicyclic epoxy compound having two alicyclic epoxy groups, for example, 3,4-epoxycyclohexenylmethyl-3,4-epoxycyclohexanecarboxylate represented by the following general formula (8) (in the general formula (8) , A is a compound of 0.), a caprolactone modified product thereof (in the general formula (8), a is a compound of 1), a trimethyl caprolactone modified product thereof (structural formula (9) and structural formula (10)), and A valerolactone modified product (Structural Formula (11) and Structural Formula (12)) or a compound represented by Structural Formula (13) can be used.

（一般式（８）中のａは０または１を表す。）

(A in the general formula (8) represents 0 or 1)

  In addition, as the alicyclic epoxy compound having two alicyclic epoxy groups, a compound represented by the following general formula (14) can also be used.

（一般式（１４）中Ｒ^１〜Ｒ^６は、それぞれ独立して、水素原子または炭素原子数1〜６のアルキル基を示す。）
前記一般式（１４）に示される化合物としては、具体的には、ジシクロヘキシル−３，３’−ジエポキシドを用いることができる。

(In the general formula (14), R ^{1 to} R ⁶ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
As the compound represented by the general formula (14), specifically, dicyclohexyl-3,3′-diepoxide can be used.

  Moreover, as an alicyclic epoxy compound which has three alicyclic epoxy groups, the compound shown by following General formula (15) can be used.

（一般式（１５）中、ａ及びｂは、それぞれ独立して０又は１であり、それらは同一であっても異なっていてもよい。）
一般式（１５）で示される脂環エポキシ化合物としては、例えばエポリードＧＴ３０１、エポリードＧＴ３０２（以上、ダイセル化学工業（株）製）等が市販されている。

(In general formula (15), a and b are each independently 0 or 1, and they may be the same or different.)
As the alicyclic epoxy compound represented by the general formula (15), for example, Epolide GT301, Epolide GT302 (manufactured by Daicel Chemical Industries, Ltd.) and the like are commercially available.

  Moreover, as an alicyclic epoxy compound which has four alicyclic epoxy groups, the compound shown, for example by following General formula (16) can be used.

（前記一般式（１６）中、ａ〜ｄは、それぞれ独立して０又は１を示し、それらは同一であっても異なっていてもよい。）
前記一般式（１６）で示される脂環エポキシ化合物としては、例えば、エポリードＧＴ４０１、エポリードＧＴ４０３（以上、ダイセル化学工業（株）製）等が市販されている。

(In the general formula (16), a to d each independently represent 0 or 1, and they may be the same or different.)
As the alicyclic epoxy compound represented by the general formula (16), for example, Epolide GT401, Epolide GT403 (manufactured by Daicel Chemical Industries, Ltd.) and the like are commercially available.

Next, the cationic polymerization initiator (D) used in the present invention will be described.
The cationic polymerization initiator (D) refers to a compound that generates an acid capable of initiating cationic polymerization upon irradiation with energy rays such as ultraviolet rays.

In the cationic polymerization initiator (D), for example, the cation moiety is aromatic sulfonium, aromatic iodonium, aromatic diazonium, aromatic ammonium, thianthrhenium, thioxanthonium, (2,4-cyclopentadiene-1- Yl) [(1-methylethyl) benzene] -Fe cation, and the anion moiety is BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , [BX ₄ ] ⁻ (where X is at least two fluorine atoms or An onium salt composed of a phenyl group substituted with a trifluoromethyl group) can be used alone or in combination of two or more.

  Examples of the aromatic sulfonium salt include bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluoroantimonate, and bis [4- ( Diphenylsulfonio) phenyl] sulfide bistetrafluoroborate, bis [4- (diphenylsulfonio) phenyl] sulfide tetrakis (pentafluorophenyl) borate, diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate, diphenyl-4- ( Phenylthio) phenylsulfonium hexafluoroantimonate, diphenyl-4- (phenylthio) phenylsulfonium tetrafluoroborate, diphenyl-4- (phenyl) Thio) phenylsulfonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, bis [4- ( Di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluoroantimony Bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bistetrafluoroborate, bis [4- (Di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide tetrakis (pentafluorophenyl) borate and the like can be used.

  Examples of the aromatic iodonium salt include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis (pentafluorophenyl) borate, and bis (dodecylphenyl) iodonium hexafluorophosphate. Bis (dodecylphenyl) iodonium hexafluoroantimonate, bis (dodecylphenyl) iodonium tetrafluoroborate, bis (dodecylphenyl) iodonium tetrakis (pentafluorophenyl) borate, 4-methylphenyl-4- (1-methylethyl) phenyl Iodonium hexafluorophosphate, 4-methylphenyl-4- (1-methyl Ruethyl) phenyliodonium hexafluoroantimonate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium tetrafluoroborate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium tetrakis (pentafluorophenyl) borate Etc. can be used.

  Examples of the aromatic diazonium salt include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, and phenyldiazonium tetrakis (pentafluorophenyl) borate.

  Examples of the aromatic ammonium salt include 1-benzyl-2-cyanopyridinium hexafluorophosphate, 1-benzyl-2-cyanopyridinium hexafluoroantimonate, 1-benzyl-2-cyanopyridinium tetrafluoroborate, 1-benzyl 2-cyanopyridinium tetrakis (pentafluorophenyl) borate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluorophosphate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluoroantimonate, 1- (naphthylmethyl) -2-Cyanopyridinium tetrafluoroborate, 1- (naphthylmethyl) -2-cyanopyridinium tetrakis (pentafluorophenyl) borate, and the like can be used.

  Moreover, S-biphenyl 2-isopropyl thioxanthonium hexafluorophosphate etc. can be used as said thioxanthonium salt.

  The (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe salt includes (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene. ] -Fe (II) hexafluorophosphate, (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe (II) hexafluoroantimonate, 2,4-cyclopentadiene-1- Yl) [(1-methylethyl) benzene] -Fe (II) tetrafluoroborate, 2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe (II) tetrakis (pentafluorophenyl) ) Borate or the like can be used.

  Examples of the cationic polymerization initiator (D) include CPI-100P, CPI-101A, CPI-110P, CPI-200K, CPI-210S (manufactured by San Apro Co., Ltd.), and Cyracure photocuring initiator UVI-6990. , Syracure photocuring initiator UVI-6922, Syracure photocuring initiator UVI-6976 (manufactured by Dow Chemical Japan Co., Ltd.), Adekaoptomer SP-150, Adekaoptomer SP-152, Adekaoptomer SP- 170, Adekaoptomer SP-172, Adekaoptomer SP-300 (above, manufactured by ADEKA Corporation), CI-5102, CI-2855 (above, manufactured by Nippon Soda Co., Ltd.), Sun-Aid SI-60L, Sun-Aid SI -80L, Sun-Aid SI-100L, Sun-Aid SI-110L, Sun Id SI-180L, Sun Aid SI-110, Sun Aid SI-180 (above, manufactured by Sanshin Chemical Industry Co., Ltd.), Esacure 1064, Esacure 1187 (above, manufactured by Lamberti), Omnicat 550 (produced by IG Resin Co., Ltd.) ), Irgacure 250 (manufactured by BASF Japan Ltd.), Rhodosil Photoinitiator 2074 (RHODORSIL PHOTOINITITOR 2074 (manufactured by Rhodia Japan Ltd.)) and the like are commercially available.

  As for the usage-amount of the said cationic polymerization initiator (D), it is desirable to use in the range of 5-50 mass parts as an active ingredient with respect to 100 mass parts of said aromatic glycidyl ethers (A).

  The cationic polymerizable adhesive of the present invention may further contain a silane coupling agent (E) having an epoxy group in order to improve the adhesive strength and the strength of the adhesive layer coating film.

  Examples of the silane cup agent (E) having an epoxy group include 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) propyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ) Alicyclic epoxy group-containing silane coupling agents such as propylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) propyltriethoxysilane, 2- (3,4-epoxycyclohexyl) propylmethyldiethoxysilane, 3- Glycidoxypropyl trimethoxy Silane, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl methyl diethoxy silane, 3-glycidoxypropyl silane coupling agents such as methyldimethoxysilane, or the like can be used. These silane cup agents may be used alone or in combination of two or more.

  Among these, from the viewpoint of further improving the adhesive strength, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltri It is more preferable to use one or more selected from the group consisting of methoxysilane and 3-glycidoxypropyltriethoxysilane.

  The amount of the silane coupling agent (E) having an epoxy group is preferably used in the range of 5 to 100 parts by mass with respect to 100 parts by mass of the aromatic glycidyl ether (A).

  The cationic polymerizable adhesive of the present invention may further contain a photosensitizer (F).

  When the cationic polymerizable adhesive of the present invention is used for adhesion between a polarizer and a protective film, the cationic polymerizable adhesive is applied on the protective film, and then the polarizer is placed on the application surface. Then, from the protective film side, UV irradiation described later may be performed to cure the cationic polymerizable adhesive. In such a case, when using a protective film (for example, a TAC film) that does not easily transmit light having a wavelength of 380 nm or more as the protective film, the photosensitizer (F) may be included in the cationic polymerizable composition. From the viewpoint of improving the curability of the adhesive, it is preferable.

  As the photosensitizer (F), for example, anthracene, anthraquinone, thioxanthone, benzophenone, benzoin isopropyl ether, and derivatives of these compounds can be used. Among these, for the reasons described above, it is preferable to use a material that exhibits maximum absorption in light having a wavelength of 380 nm or more, and it is more preferable to use an anthracene compound.

  Examples of the anthracene compound exhibiting maximum absorption in light having a wavelength of 380 nm or more include 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, and 9,10-diisopropoxy. Anthracene, 9,10-dibutoxyanthracene, 9,10-dipentyloxyanthracene, 9,10-dihexyloxyanthracene, 9,10-bis (2-methoxyethoxy) anthracene, 9,10-bis (2-ethoxyethoxy) Anthracene, 9,10-bis (2-butoxyethoxy) anthracene, 9,10-bis (3-butoxypropoxy) anthracene, 2-methyl or 2-ethyl-9,10-dimethoxyanthracene, 2-methyl or 2-ethyl -9,10-diethoxyanthracene 2-methyl or 2-ethyl-9,10-dipropoxyanthracene, 2-methyl or 2-ethyl-9,10-diisopropoxyanthracene, 2-methyl or 2-ethyl-9,10-dibutoxyanthracene, 2 -Methyl or 2-ethyl-9,10-dipentyloxyanthracene, 2-methyl or 2-ethyl-9,10-dihexyloxyanthracene and the like can be used. Examples of the anthracene compounds are commercially available (“UVS-1331” manufactured by Kawasaki Chemical Co., Ltd.), Kayacure DETX-S (manufactured by Nippon Kayaku Co., Ltd.), and the like.

  As for the usage-amount of the said photosensitizer (F), it is desirable to use 0.5-10 mass parts with respect to 100 mass parts of said aromatic glycidyl ethers (A).

  Moreover, when using the said photosensitizer (F), in order to expand the sensitization wavelength range of the said cation initiator (D) and to further improve the sclerosis | hardenability of the cation polymeric adhesive of this invention, A photosensitizing aid (G) can also be used.

  As the photosensitization aid (G), for example, nitrofluorene, naphthalene compounds, and the like can be used, and 1,4-dimethoxynaphthalene, 1-ethoxy-4-methoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-dipropoxynaphthalene, 1,4-dibutoxynaphthalene and the like can be preferably used.

  As for the usage-amount of the said photosensitization adjuvant (G), it is desirable to use 0.5-10 mass parts with respect to 100 mass parts of said aromatic glycidyl ethers (A).

  Next, the cationic polymerizable adhesive of the present invention will be described.

  The cationic polymerizable adhesive of the present invention includes the aromatic glycidyl ether (A), the oxetane compound (B), the alicyclic epoxy compound (C), and the cationic polymerization initiator (D), if necessary. The epoxy group-containing silane coupling agent (E), the photosensitizer (F), and the photosensitization aid (G) are contained within a range that does not impair the effects of the present invention. Various additives may be contained.

  Examples of the additive include a thixotropic agent, a leveling agent, an antioxidant, a tackifier, a wax, a heat stabilizer, a light stabilizer, a fluorescent brightening agent, a foaming agent, a thermoplastic resin, a thermosetting resin, Organic solvent, conductivity imparting agent, antistatic agent, moisture permeability improver, water repellent, hollow foam, crystal water-containing compound, flame retardant, water absorbent, moisture absorbent, deodorant, foam stabilizer, defoamer Antifungal agents, antiseptics, antialgae agents, antiblocking agents, antihydrolysis agents, organic and inorganic water-soluble compounds, and the like can be used.

  In addition to the above, for the purpose of further reducing the rigidity of the cationic polymerizable adhesive of the present invention, a polyol such as a polyether polyol may be contained.

  In addition to the polyol, the cationically polymerizable adhesive of the present invention may contain a cationically polymerizable compound such as vinyl ether or oxolane for the purpose of further improving curability and viscosity reduction.

  Examples of the vinyl ether include butanediol divinyl ether, hexanediol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, neopentyl glycol divinyl ether, cyclohexane dimethanol divinyl ether, and the like.

  The cationically polymerizable adhesive of the present invention has low viscosity, and the viscosity at normal temperature is in the range of 10 to 100 mPa · s. The viscosity of the cationic polymerizable adhesive is a value measured with a B-type viscometer at 25 ° C.

  Next, the manufacturing method of the cation polymerizable adhesive of this invention is demonstrated. The cationically polymerizable adhesive of the present invention can be produced, for example, by the following method.

  The cationic polymerizable adhesive of the present invention is prepared by using, for example, a container equipped with a stirrer, the aromatic glycidyl ether (A), the oxetane compound (B), the alicyclic epoxy compound (C), It can be produced by mixing and stirring the cationic polymerization initiator (D) and, if necessary, the various additives.

  The cationic polymerizable adhesive of the present invention can be cured by irradiation with energy rays such as ultraviolet rays. The cationically polymerizable adhesive of the present invention exhibits adhesiveness only after irradiation with energy rays such as ultraviolet rays.

Irradiation of energy rays such as the ultraviolet light, preferably in the range of 10~5000mJ / cm ^2, more preferably from 20~2500mJ / cm ^2, particularly preferably it is in the range of 30~1500mJ / cm ^2.

  For example, a known lamp such as a xenon lamp, a xenon-mercury lamp, a metal halide lamp, a high-pressure mercury lamp, or a low-pressure mercury lamp can be used as the ultraviolet ray generation source. In addition, the ultraviolet irradiation amount is based on a value measured in a wavelength region of 300 to 390 nm using a UV checker; UV Power PucK (II) (manufactured by Electronic Instrumentation and Technology).

  Moreover, you may accelerate | stimulate hardening further by heating at about 40-80 degreeC after irradiation of the said energy ray as needed.

  Next, the polarizing plate of the present invention will be described.

  The polarizing plate of the present invention is obtained by bonding a protective film and a polarizer via an adhesive layer made of the cationic polymerizable adhesive.

  Examples of the protective film include acrylic resin, silicon resin, epoxy resin, fluorine resin, polystyrene resin, polyester resin, polysulfone resin, polyarylate resin, polyvinyl chloride resin, polyvinylidene chloride, norbornene, and the like. Cycloolefin resin, amorphous polyolefin resin, polyimide resin, alicyclic polyimide resin, cellulose resin, PC (polycarbonate), PBT (polybutylene terephthalate), modified PPE (polyphenylene ether), PEN ( Polyethylene naphthalate), a film using PET (polyethylene terephthalate) or the like, or a biodegradable film such as a polylactic acid polymer can be used.

  As the acrylic resin, an acrylic resin or a thermoplastic acrylic resin having a glass transition temperature (Tg) of 100 ° C. or higher can be used, and elastic particles having a number average particle diameter of 2.0 μm or less are contained in the acrylic resin. It is good also as a protective film in which the elastic body particle is unevenly distributed in the thickness direction center part of the protective film.

  The thickness of the protective film used when producing the polarizing plate of the present invention varies depending on the application used, but is preferably in the range of about 20 μm to 100 μm. Moreover, it is preferable that the thickness of the polarizer is generally in the range of about 5 μm to 50 μm.

  In addition, the polarizer is not particularly limited, and various types can be used. For example, hydrophilic polymers such as polyvinyl alcohol, partially formalized polyvinyl alcohol, and ethylene / vinyl acetate copolymer partially saponified products. A dichroic material obtained by adsorbing a dichroic material such as iodine or a dichroic dye to a plastic substrate made of a compound and uniaxially stretching the surface of a stretched film obtained by uniaxially stretching the plastic substrate. Polyene-based oriented films such as materials adsorbed, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products can be used. Among these, it is preferable to use a film in which a polyvinyl alcohol film and a dichroic substance such as iodine are adsorbed.

  In the polarizing plate of the present invention, for example, the cationic polymerizable adhesive is coated on the protective film, and then the coated surface is irradiated with the above-mentioned amount of ultraviolet light, and then a polarizer is mounted on the coated surface. It can also be produced by placing and adhering, and the cationic polymerizable adhesive is coated on the protective film, and then a polarizer is placed on the coated surface, and then from the protective film side. It can also be produced by irradiating the aforementioned amount of ultraviolet rays. In the polarizing plate of the present invention, the cationic polymerizable adhesive is coated on the polarizer, and then the coated surface is irradiated with the above-described amount of ultraviolet light, and then a protective film is placed on the coated surface. It can also be produced by bonding, and the cationic polymerizable adhesive is applied on the polarizer, and then a protective film is placed on the coated surface, and then the protective film side as described above. It can also be produced by irradiating an amount of ultraviolet light. When producing the polarizing plate of the present invention, the thickness of the adhesive layer made of the cationic polymerizable adhesive is preferably as thin as possible for reasons such as optical properties being impaired, and specifically, it is 5 μm or less. Is preferred.

  The polarizing plate of the present invention is, for example, coated on one surface of two protective films with the cationic polymerizable adhesive, and then irradiated with the above amount of ultraviolet rays on the coated surface. May be placed on both sides of the polarizer and bonded to form a laminate of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymeric adhesive layer / protective film from above. In addition, the cationic polymerizable adhesive is applied to one side of each of the two protective films, the applied surface is placed on both sides of the polarizer, and then the above-described amount of ultraviolet rays is irradiated to the surface. A laminate can also be produced.

  The method for applying the cationic polymerizable adhesive is not particularly limited. For example, it is applied by a slit coater method such as a curtain flow coater method or a die coater method, a knife coater method, a roll coater method, a gravure coater method, a spray, or the like. Can be used.

  The polarizing plate of the present invention obtained by the above method can be used as a member constituting a display such as a mobile communication terminal such as a mobile phone, a liquid crystal television, a personal computer, and a portable game machine.

  Hereinafter, the present invention will be described in detail by way of examples.

[Production method of polarizer]
Kuraraypoval PVA-117H (polyvinyl alcohol manufactured by Kuraray Co., Ltd., degree of polymerization 1700, completely saponified product, powder) dissolved in water with a polyvinyl alcohol aqueous solution (non-volatile content 8% by mass), a bar coater The film was applied onto a release film and then dried for 5 minutes in an environment of 80 ° C., and then the release film was removed to prepare a polyvinyl alcohol film having a thickness of 75 μm.
Next, the obtained polyvinyl alcohol film was fixed to a stretching machine, and the film was stretched in hot water at 40 ° C. until it became three times larger in a uniaxial direction.
After removing water adhering to the surface of the stretched film obtained above, the stretched film was adjusted to 30 ° C. containing 0.02 parts by mass of iodine, 2 parts by mass of potassium iodide and 100 parts by mass of water. It was immersed in the aqueous solution.
Next, the stretched film was immersed in an aqueous solution adjusted to 56.5 ° C. containing 12 parts by mass of potassium iodide, 5 parts by mass of boric acid, and 100 parts by mass of water.
After the immersed stretched film is washed in pure water adjusted to 8 ° C. and dried in an environment of 65 ° C., a polarizer in which iodine is adsorbed and oriented on the surface of the stretched film made of polyvinyl alcohol (polarized light) Film).

[ Reference Example 1]
100 parts by mass of EPICLON EXA-830CRP as an aromatic glycidyl ether (A) in a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, oxetane compound having two or more oxetanyl groups As (B), 150 parts by mass of Alonoxetane OXT-221, alicyclic epoxy compound (C), 250 parts by mass of Celoxide 3000, and cationic polymerization initiator (D) as diphenyl-4- (phenylthio) phenylsulfonium hexa A cationic polymerizable adhesive having a viscosity of 23 mPa · s (25 ° C.) was prepared by mixing and stirring 40 parts by mass of a propylene carbonate 50% by mass solution of fluorophosphate.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after applying pressure using a rubber roller, an integrated light amount of 300 to 390 nm from the acrylic resin film side using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min). However, the polarizing plate which has the structure of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above by irradiating ultraviolet rays of 1300 mJ / cm ² .

[ Reference Example 2]
100 parts by mass of EPICLON EXA-830CRP as an aromatic glycidyl ether (A) in a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, oxetane compound having two or more oxetanyl groups (B) 200 parts by mass of Alonoxetane OXT-221, alicyclic epoxy compound (C), 200 parts by mass of Celoxide 3000, and cationic polymerization initiator (D) as diphenyl-4- (phenylthio) phenylsulfonium hexa A cationic polymerizable adhesive having a viscosity of 24 mPa · s (25 ° C.) was prepared by mixing and stirring 40 parts by mass of a 50 mass% propylene carbonate solution of fluorophosphate.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after pressurizing with a rubber roller, using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min), the accumulated light amount of 300 to 390 nm on the acrylic resin film side is By irradiating ultraviolet rays of 1300 mJ / cm ² , a polarizing plate having a configuration of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above.

[ Reference Example 3]
100 parts by mass of EPICLON EXA-830CRP as an aromatic glycidyl ether (A) in a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, oxetane compound having two or more oxetanyl groups As (B), 237.5 parts by mass of Alonoxetane OXT-221, alicyclic epoxy compound (C), 162.5 parts by mass of Celoxide 3000, and cationic polymerization initiator (D) as diphenyl-4- (phenylthio) ) A cationic polymerizable adhesive having a viscosity of 24 mPa · s (25 ° C.) was prepared by mixing and stirring 40 parts by mass of a propylene carbonate 50% by mass solution of phenylsulfonium hexafluorophosphate.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after pressurizing using a rubber roller, a cumulative light quantity of 300 to 390 nm is obtained from the acrylic resin film side using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min). By irradiating ultraviolet rays of 1300 mJ / cm ² , a polarizing plate having a configuration of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above.

[Example 1 ]
100 parts by mass of EPICLON EXA-830CRP as an aromatic glycidyl ether (A) in a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, oxetane compound having two or more oxetanyl groups As (B), 225 parts by mass of Alonoxetane OXT-221, alicyclic epoxy compound (C), 125 parts by mass of Celoxide 3000, and cationic polymerization initiator (D) as diphenyl-4- (phenylthio) phenylsulfonium hexa 40 parts by mass of a 50 mass% propylene carbonate solution of fluorophosphate and 50 parts by mass of 2- (3,4-epoxycyclohexylethyltrimethoxysilane) as an epoxy group-containing silane coupling agent (E) are mixed and stirred. A viscosity of 24 mPa A s (25 ° C.) cationic polymerizable adhesive was prepared.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after applying pressure using a rubber roller, an integrated light amount of 300 to 390 nm from the acrylic resin film side using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min). However, the polarizing plate which has the structure of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above by irradiating ultraviolet rays of 1300 mJ / cm ² .

[ Reference Example 4 ]
100 parts by mass of EPICLON EXA-830CRP as an aromatic glycidyl ether (A) in a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, oxetane compound having two or more oxetanyl groups As (B), 350 parts by mass of Alonoxetane OXT-221, 50 parts by mass of Celoxide 3000 as an alicyclic epoxy compound (C), and diphenyl-4- (phenylthio) phenylsulfonium hexa as a cationic polymerization initiator (D) A cationic polymerizable adhesive having a viscosity of 24 mPa · s (25 ° C.) was prepared by mixing and stirring 40 parts by mass of a 50 mass% propylene carbonate solution of fluorophosphate.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after applying pressure using a rubber roller, an integrated light amount of 300 to 390 nm from the acrylic resin film side using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min). However, the polarizing plate which has the structure of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above by irradiating ultraviolet rays of 1300 mJ / cm ² .

[ Comparative Example 6]
100 parts by mass of EPICLON EXA-830CRP as an aromatic glycidyl ether (A) in a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, oxetane compound having two or more oxetanyl groups As (B), 375 parts by mass of Alonoxetane OXT-221, alicyclic epoxy compound (C), 25 parts by mass of Celoxide 3000, and cationic polymerization initiator (D) as diphenyl-4- (phenylthio) phenylsulfonium hexa A cationic polymerizable adhesive having a viscosity of 25 mPa · s (25 ° C.) was prepared by mixing and stirring 40 parts by mass of a propylene carbonate 50% by mass solution of fluorophosphate.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after applying pressure using a rubber roller, an integrated light amount of 300 to 390 nm from the acrylic resin film side using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min). However, the polarizing plate which has the structure of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above by irradiating ultraviolet rays of 1300 mJ / cm ² .

[Comparative Example 1]
100 parts by mass of EPICLON EXA-830CRP as an aromatic glycidyl ether (A) in a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, oxetane compound having two or more oxetanyl groups As (B), 400 parts by mass of Alonoxetane OXT-221 and 40 parts by mass of a propylene carbonate 50% by mass solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate as a cationic polymerization initiator (D) were mixed. The cationic polymerizable adhesive having a viscosity of 24 mPa · s (25 ° C.) was prepared by stirring.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after applying pressure using a rubber roller, an integrated light amount of 300 to 390 nm from the acrylic resin film side using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min). However, the polarizing plate which has the structure of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above by irradiating ultraviolet rays of 1300 mJ / cm ² .

[Comparative Example 2]
100 parts by mass of EPICLON EXA-830CRP as an aromatic glycidyl ether (A) in a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, oxetane compound having two or more oxetanyl groups As (B), 395 parts by mass of Alonoxetane OXT-221, alicyclic epoxy compound (C), 5 parts by mass of Celoxide 3000, and cationic polymerization initiator (D) as diphenyl-4- (phenylthio) phenylsulfonium hexa A cationic polymerizable adhesive having a viscosity of 25 mPa · s (25 ° C.) was prepared by mixing and stirring 40 parts by mass of a propylene carbonate 50% by mass solution of fluorophosphate.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after applying pressure using a rubber roller, an integrated light amount of 300 to 390 nm from the acrylic resin film side using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min). However, the polarizing plate which has the structure of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above by irradiating ultraviolet rays of 1300 mJ / cm ² .

[Comparative Example 3]
100 parts by mass of EPICLON EXA-830CRP as an aromatic glycidyl ether (A) in a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, oxetane compound having two or more oxetanyl groups As (B), 100 parts by mass of Alonoxetane OXT-221, alicyclic epoxy compound (C), 300 parts by mass of Celoxide 3000, and cationic polymerization initiator (D) as diphenyl-4- (phenylthio) phenylsulfonium hexa A cationic polymerizable adhesive having a viscosity of 23 mPa · s (25 ° C.) was prepared by mixing and stirring 40 parts by mass of a propylene carbonate 50% by mass solution of fluorophosphate.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after applying pressure using a rubber roller, an integrated light amount of 300 to 390 nm from the acrylic resin film side using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min). However, the polarizing plate which has the structure of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above by irradiating ultraviolet rays of 1300 mJ / cm ² .

[Comparative Example 4]
100 parts by mass of EPICLON EXA-830CRP as an aromatic glycidyl ether (A) in a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, oxetane compound having two or more oxetanyl groups As (B), 50 parts by mass of Alonoxetane OXT-221, 400 parts by mass of Celoxide 3000 as an alicyclic epoxy compound (C), and diphenyl-4- (phenylthio) phenylsulfonium hexa as a cationic polymerization initiator (D) A cationic polymerizable adhesive having a viscosity of 22 mPa · s (25 ° C.) was prepared by mixing and stirring 40 parts by mass of a 50 mass% propylene carbonate solution of fluorophosphate.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after applying pressure using a rubber roller, an integrated light amount of 300 to 390 nm from the acrylic resin film side using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min). However, the polarizing plate which has the structure of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above by irradiating ultraviolet rays of 1300 mJ / cm ² .

[Comparative Example 5]
A reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, as aromatic glycidyl ether (A), 100 parts by mass of EPICLON EXA-830CRP, as alicyclic epoxy compound (C), ceroxide By mixing and stirring 40 parts by mass of a propylene carbonate 50 mass% solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate with 400 parts by mass of 3000 and cationic polymerization initiator (D), a viscosity of 22 mPa · An s (25 ° C.) cationic polymerizable adhesive was prepared.
The obtained cationic polymerizable adhesive was applied to each surface of the acrylic resin film and the TAC film so as to have a thickness of about 2 μm using a wire bar, and the coated substrate was coated with the polarizer ( It was bonded to both sides of the polarizing film). Next, after applying pressure using a rubber roller, an integrated light amount of 300 to 390 nm from the acrylic resin film side using a conveyor type ultraviolet irradiation device (Fusion LH-6 output 100%, conveyor speed 17.8 m / min). However, the polarizing plate which has the structure of protective film / cationic polymerizable adhesive layer / polarizer / cationic polymerizable adhesive layer / protective film was obtained from above by irradiating ultraviolet rays of 1300 mJ / cm ² .

[Evaluation method of adhesive strength]
The adhesive strength was evaluated by the following two items.

(90 degree peel strength)
Samples obtained by cutting the polarizing plates obtained in Examples , Reference Examples and Comparative Examples into a width of 80 mm and a width of 25 mm were used as test pieces. The acrylic resin film side of the test piece is attached to an aluminum plate as an adherend, and adhesive No. 5601 (manufactured by Nitto Denko Co., Ltd.), the laminated part where the polarizer and the TAC film at the end are bonded together is peeled off from the acrylic resin film side, and the speed is 10 mm / min according to JIS Z-0237. The 90 ° peel strength was measured in an atmosphere of 23 ° C. and 50% RH.
In addition, 90 degree peel strength is
What is 3N / 25 mm or more, “○”,
What is 1.5N / 25mm or more and less than 3N / 25mm, "△",
What is less than 1.5N / 25mm, "x",
It was evaluated.

(Destruction mode)
The peeled surface after the 90 degree peel strength test was visually observed and judged as follows.
CF: cohesive failure of the cationic polymerizable adhesive layer,
AF: peeling of the cationic polymerizable adhesive layer from the acrylic resin film,
In addition, what is CF is destruction of the cation polymerizable adhesive layer, and since the cation polymerizable adhesive is adhered to the acrylic resin film, it is determined that the adhesive strength to the acrylic resin film is good. ○ ”.
Also, in the case of AF, since the cationic polymerizable adhesive layer was peeled off from the acrylic resin film, it was judged that the adhesive strength to the acrylic resin film was poor, and “x” was assigned.

Abbreviations in Tables 1 and 2 will be described.
“EPICLON EXA-830CRP”; bisphenol F diglycidyl ether “Aron oxetane OXT-221”; bis [1-ethyl (3-oxetanyl)] methyl ether “ceroxide 3000”; 1,2: 8,9-diepoxy limonene “ KBM-303 "; 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane

Example 1 which is a cationically polymerizable adhesive of the present invention Was found to have excellent adhesive strength, especially for acrylic resin films.
On the other hand, although the comparative example 1 is an aspect which does not contain an alicyclic epoxy compound, it turned out that adhesive strength is unsatisfactory.
In Comparative Examples 2 to 4, the mass ratios of the oxetane compound and the alicyclic epoxy compound deviate from the range defined in the present invention, but it was found that the adhesive strength was poor.
Moreover, although the comparative example 5 is an aspect which does not contain an oxetane compound, it turned out that adhesive strength is unsatisfactory.

Claims (4)

Contains an aromatic glycidyl ether (A), an oxetane compound (B) having two or more oxetanyl groups, an alicyclic epoxy compound (C) represented by the following general formula (7), and a cationic polymerization initiator (D) A cationically polymerizable adhesive that comprises:
The aromatic glycidyl ether (A) is at least one selected from the group consisting of bisphenol A diglycidyl ether and bisphenol F diglycidyl ether, and the oxetane compound (B) is represented by the following general formula ( 2 ). The oxetane compound (B) is used in the range of 120 to 360 parts by mass with respect to 100 parts by mass of the aromatic glycidyl ether (A), and the alicyclic epoxy compound (C) is 35 to 280 parts by mass. 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane and 3-glycidoxy One or more epoxy groups selected from the group consisting of propyltriethoxysilane Cationic polymerizable adhesive which is characterized by containing a silane coupling agent (E) with.

(In formula (7), R ¹ , R ² and R ³ each independently represents a hydrogen atom or a methyl group.)

(In the general formula (2), R ¹ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, Z is an acid atom or a sulfur atom. ) The cationically polymerizable adhesive according to claim 1, wherein the oxetane compound (B) is bis [1-ethyl (3-oxetanyl)] methyl ether. The cationically polymerizable adhesive according to claim 1, wherein the alicyclic epoxy compound (C) is 1,2: 8,9-diepoxy limonene. It is a polarizing plate with which the protective film and the polarizer were adhere | attached through the cationic polymerizable adhesive, Comprising: The said cationic polymerizable adhesive is a cationic polymerizable adhesive of any one of Claims 1-3. A polarizing plate characterized by that.